量子化学计算及分子对接技术对豌豆蛋白源抗氧化肽YLVN、TFY的抗氧化作用机制研究

Research on antioxidant mechanism of pea protein-derived antioxidant peptides YLVN and TFY based on quantum chemical calculation and molecular docking technology

中文关键词:  抗氧化肽  量子化学计算  分子对接  抗氧化机制

英文关键词:antioxidant peptides  quantum chemical calculation  molecular docking  antioxidant mechanism

中文摘要:

      目的 探究豌豆蛋白源抗氧化肽YLVN、TFY的抗氧化机制。方法 利用量子化学理论计算构建抗氧化肽的优势构象, 前线轨道分布及能级差(ΔE)和福井函数(Fukui)中的f0(r)对二者活性位点进行了推测; 分子对接技术对抗氧化肽与1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-trinitrophenylhydrazine, DPPH)和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐[2,2-diazo-di (3-ethyl-benzothiazol-6-sulfonic acid) diamiammonium salt, ABTS]自由基的清除作用机制进行了探究, 并通过体外自由基清除实验验证肽的活性, 将理论计算和实验测定进行分析比对。结果 前线分子轨道中的最高占据分子轨道(highest occupied molecular orbital, HOMO)及轨道能级确定酪氨酸(Tyr)残基是肽YLVN、TFY重要的活性位点, 与Fukui函数f0(r)推断肽YLVN 中Tyr的酚羟基O14-H47和肽TFY中Tyr的酚羟基O26-H52是重要的活性位点基本一致。同时, 进一步对Fukui函数确定的活性位点处的Mulliken电荷分析, 推测酚羟基的-OH键通过释放H原子与自由基结合中断自由基的链式反应; 分子对接结果表明YLVN、TFY可以分别与DPPH和ABTS自由基通过形成氢键相互作用具有较强的自由基清除能力, 理论预测与体外化学实验结果基本一致。结论 豌豆蛋白源抗氧化肽YLVN、TFY具有较强的自由基清除能力, 本研究为抗氧化肽的结构机制和抗氧化机制探究提供了理论基础。

英文摘要:

      Objective To explore the antioxidant mechanism of pea protein-derived antioxidant peptides YLVN and TFY. Methods The quantum chemical theoretical calculation methods were used to calculate the optimized geometric structure and predicted the active sites of YLVN and TFY by the front-line orbital distribution, energy difference (ΔE) and Fukui index f0(r). The mechanism of action between antioxidant peptides and 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and 2,2-diazo-di (3-ethyl-benzothiazol-6-sulfonic acid) diamiammonium salt (ABTS) free radicals was explored by molecular docking technology, and the activities of the peptides were verified by free radical scavenging assay in vitro, the theoretical calculations and experimental measurements were analyzed and compared. Results The tyrosine residues were determined to be the major active sites of YLVN and TFY by HOMO (the highest occupied molecular orbital) front-line orbital distribution and energy level, consistent with the phenolic hydroxyl O14-H47 of Tyr in peptide YLVN and the phenolic hydroxyl O26-H52 of Tyr in peptide TFY were important active sites by Fukui function f0(r). At the same time, the Mulliken charge at the active site determined by the Fukui function were further analyzed, and the -OH bond of the phenolic hydroxyl group could interrupt the chain reaction of the free radical by releasing the H atom to bind to the free radical; the molecular docking results showed that YLVN and TFY had strong free radical scavenging abilities by forming hydrogen bonds with DPPH and ABTS radicals, respectively. The theoretical predictions were basically consistent with the results of chemical experiments in vitro. Conclusion The pea protein-derived antioxidant peptides YLVN and TFY have strong free radical scavenging abilities, and this study provides a theoretical basis for the exploration of the structural mechanism and antioxidant mechanism of antioxidant peptides.